It hasn’t. You have vestigial organs of no current use (the appendix, male teats, democrats) that are pretty clear signs that we are evolving still and shedding no longer useful parts (obviously some not quickly enough).
If I remember, research is showing the appendix does have a useful function in fetal development . Rudimentary nipples, easy way to tell how cold it is. Democrats, you have me there...........
>>Rudimentary nipples, easy way to tell how cold it is. <<
And they do break up the chest area for models — maybe I need to rethink this... ;)